In linear guide portions of work tables of machine tools and various carrier devices, rolling guide devices each having a structure in which a mobile block mounted with a movable body such as a table continuously moves along a track rail are very often used. In this type of rolling guide device, the mobile block is combined with the track rail via a multitude of rolling bodies such as balls or rollers, and each of the rolling bodies runs in a rolling manner while applying a load between the mobile block and the track rail, so a mounted object fixed to the mobile block is allowed to make light movements along the track rail with negligible resistance.
The track rail has a rolling contact surface for regulating the rolling direction of the rolling bodies, and the rolling contact surface is required to exhibit sufficient hardness. In this type of linear guide device, therefore, the track rail itself is generally formed of a quenchable metal material or a carburized steel. The entire track rail or only a region thereof where the rolling contact surface is formed is then subjected to heat treatment such as quenching, so the hardness of the rolling contact surface is enhanced.
However, when being subjected to the heat treatment, the track rail undergoes deformations such as bending and torsion, so there is an inconvenience in that an operation of correcting such deformations becomes inevitable. Although an attempt to automate the operation of correcting the deformations of the track rail has also been made, subtle bending or subtle torsion cannot be eliminated completely. In order to achieve movements of the mobile block with high accuracy, a skilled operator needs to perform a corrective operation. This leads to a decline in the production efficiency and a rise in production cost in producing the linear guide device.
On the other hand, a linear guide device disclosed in each of JP 02-309011 A, JP 08-14254 A, JP 2002-303320 A, and the like is known as a solution to the problem described above. In the linear guide device disclosed in each of those documents, a track rail is composed of rail members equipped with rolling contact surfaces for balls and a rail housing equipped with mounting grooves for the rail members, and the rail members are fixed to the mounting grooves of the rail housing respectively using a method such as press-fitting, adhesion, or brazing. The rolling contact surfaces for the balls are formed in the rail members, respectively. Therefore, if a material exhibiting sufficient hardness is selected for the rail members, there is no need to subject the rail housing itself to heat treatment such as quenching or to perform the corrective operation following the heat treatment as described above. Further, an extruded material of aluminum alloy, a concrete molded product, or the like can also be used for the rail housing, so there is also an advantage in that the most suitable and inexpensive material corresponding to the intended purpose of the linear guide device can be selected for the rail housing.
Patent Document 1: JP 02-309011 A
Patent Document 2: JP 08-14254 A
Patent Document 3: JP 2002-303320 A